HomeMy WebLinkAbout2882 Teller StreetBest
E I neering
Solutions and
Technologies
GEOTECHNICAL ENGINEERING WheB/q,.
PAVEMENT DESIGN STUDY U w
2850-2880 TELLER STREET
WHEAT RIDGE, COLORADO
80033 �%ang D�nsoc
PROJECT NUMBER 19-1114
JULY 3, 2019
PDATED DECEMBER 23, 2019
PREPARED FOR
LUCID STUDIO LLC
7190 W 38TH AVENUE
STUDIO B
WHEAT RIDGE, COLORADO
80033
Matthew A.Best,P
Project Engg ineer
Matthew
Best
Digitally signed by
Matthew Best
Date: 2019.12.23
12:04:21 -07'00'
Locations Summit evenly & Lakawwtl, Ook2tlo • Nam 0 • PM1ma: 9]0.409.98]0 • MaastBagEnoloeanmUSA.Com
Mailing: 747 Sheritlan Boulavani, Unit 3A • LakewaW, Cdoatlo WP11• Phone: 303239.970 • O1fir¢®Bai;EmimorinoUS4.cwn
3656-3666 Teller SVert
B.E.S.T.
Rgxi Numben 19-1114
Table of Contents
EXECUTIVESUMMARY.......................................................................................................................................................................3
11
PURPOSE AND SCOPE OF WORK........................................................................................................................................................4
12
PROPOSED CONSTRUCTION...............................................................................................................................................................4
12
SITECONDITIONS..................................................................................................................................................................................4
12
FIELDEXPLORATION...........................................................................................................................................................................4
12
SUBSURFACE CONDITIONS................................................................................................................................................................4
13
FOUNDATION DESIGN RECOMMENDATIONS................................................................................................................................5
ATTACHEDGARAGE FLOOR SLABS .................... .............................................................................................................................
SURFACEDRAINAGE............................................................................................................................................................................8
UNDERDRAMSYSTEM........................................................................................................................................................................9
PAVEMENT THICKNESS DESIGN.......................................................................................................................................................9
CONSTRUCTIONDETAILS.................................................................................................................................................................
11
MAINTENANCE
12
SITE DEMOLITION
12
HOMEOWNER PRECAUTIONS
12
DESIGN AND CONSTRUCTION SUPPORT SERVICES
12
LIMITATIONS
13
TABLE
FIGURE 1—LOCATION AND SITE MAP
FIGURE 2 — LOCATION OF EXPLORATORY BORING
FIGURE 3 —BORING LOG
FIGURE 4—LEGEND AND NOTES
FIGURE 5— SWELLCONSOLIDATION TESTING
(2)
Locations Summit Counly 8 Lakawco4, Lok ado • Peg m 0 • PM1ma: 9]6.409.96]6 • MaVgBealEnoloaenmUSA.corn
Mailing: 747 Shericlan BoulavaN, Unit 3A • Lakemoc, Woatlo 09311- Phone: 363336.976 • ORiceABai;En imorinoU54.cwn
2660-2680 Tellerslreel B.E.S.T.
"il Number: 19-1114
EXECUTIVE SUMMARY
Best Engineering Solutions and Technologies, LLC (BEST) completed a geotechnical engineering study for
the project located at 2850-2880 Teller Street in Wheat Ridge, Colorado. Design parameters and a discussion
of geotechnical engineering considerations related to convection of the proposed residences are included in
this report. A summary of the findings includes:
1. Subsurface explorations encountered natural, hard, sandy clay over silty to sandy claystone bedrock.
Groundwater was not encountered during excavation of the test boring. Fluctuations of the groundwater
may occur seasonally or with precipitation events.
2. Based on the subsurface conditions encountered in the test boring and the nature of the proposed
construction, we recommend the proposed structures be founded with spread footings bearing on native
soils. Spread footings bearing as recommended should be designed for an allowable bearing pressure of
2,500 pounds per square foot (pat).
3. Using the design resilient modulus (Ma) and the assumed ESALs identified in the report, flexible
pavements used for the automobile parking areas should be constructed with a minimum of 5.0 inches of
full -depth asphalt. As an alternative to the full -depth asphalt recommendations, a composite section
consisting of 3.5 inches of asphalt over 6 inches of aggregate base course may be used for the parking
areas. Areas requiring Portland Cement Concrete should be constructed with a minimhun of 6.0 inches of
concrete.
4. Interior Boors of the residence will be structurally supported over a crawl space. Soil beneath attached
garage slabs should be over -excavated to a minimum depth of 12 inches and replaced with an imported
structural fill or a non -expansive, predominantly granular material. Native soils or imported structural fill
are suitable for support of exterior Batwork.
5. A representative of our office should observe the construction operations discussed in this report.
6. Keep any exposed soils from excessive drying or wetting during the construction process.
7. More detailed recommendations are made throughout this report. These must be reviewed to assure proper
consideration in the design.
(3)
Locations 5ummtl evenly a Laaevoo 1, eak2tlo - PasM 0 - PM1ma: 9]0.409.96]6- MattrilBeslEnulnaeamUSA.corn
Mailing: 747 Sheridan Boulavani, Und 2A - Lakemoc, Coloatlo 80211- Phone: 303.239.970 - ORiceABeslEmineerinoUS4.cwn
3050-3080 Teller street B.E.S.T.
Pr iNadi19-1114
PURPOSE AND SCOPE OF WORK
This report presents the results of a geotechnical engineering study and pavement design study for the project
located at 2850-2880 Teller Street in Wheat Ridge, Colorado. The project site is shown on Figure 1. The study
was conducted to provide foundation design and support of slabs-on-grade recommendations.
A field exploration study consisting of one exploratory boring was conducted to collect information on the
subsurface conditions. Samples of the subsoils collected during the field exploration were tested in the
laboratory to determine their classification and engineering characteristics. The results of the field exploration
and laboratory testing were analyzed to develop recommendations for foundation types, depths, and allowable
pressures for the proposed building foundations.
This report has been prepared to summarize the data obtained during this study and to present our conclusions
and recommendations based on the proposed construction and the subsurface conditions encountered. Design
parameters and a discussion of geotechnical engineering considerations related to construction of the proposed
residences are included in this report.
PROPOSED CONSTRUCTION
We understand that the proposed construction will consist of the demolition of the existing structure and
construction of six single -family homes over crawlspaces with attached and detached garages. Conventional
wood frame construction, with column loads expected to be low to moderate and typical of this type of
structure, will be used above grade with cast-in-place concrete foundations below grade. Ground Boors will be
slab-on-grade. Site development is expected to include sidewalk and landscaped men. Local utilities will
generally be underground, except for surface storm runoff and overhead electric.
If the loadings, locations, or grading plans for the structures change significantly from those described above,
we should be notified to re-evaluate the recommendations contained in this report.
SITE CONDITIONS
At the time of our field exploration, the property consisted of a single -family residence and adjacent vacant lot.
The site is bounded by residential single -family homes. The topography in the am slopes toward the north and
east and is at an approximate elevation of 5,460 feet MSL.
FIELD EXPLORATION
The exploratory boring was drilled on June 18, 2(1 approximately at the location shown on Figure 2 to
evaluate the subsurface conditions. The boring was drilled using a truck-mounted rig and was logged by a
representative of BEST. Samples of the soils were taken with undisturbed sampling methods and the depth of
the boring and samples are shown on the Boring Log, Figure 3 and Legend and Notes, Figure 4.
SUBSURFACE CONDITIONS
In Borehole 1, natural medium stiff to stiff silty and sandy clay was encountered to a depth of approximately
24 feet. Olive claystone was encountered to the depth explored of 25 feet. The soils encountered were slightly
moist to very moist. Groundwater was initially encountered at a depth of 16 feet, and was found at 12 feet
when measured 72 hours later.
In Borehole 2, natural medium stiff to stiff silty and sandy clay was encountered to the depth explored of 20
feet. The soils encountered were slightly moist to very moist. Groundwater was encountered at the very bottom
of the hole at the time of the boring. Fluctuations in the groundwater levels may occur seasonally or with
precipitation events.
(4)
Locations, Saudi county a Lakexmtl, cok2tlo • PasM 0 • Phi 9]0.409.90]0- MatlgrBaslEnalneenmUSh.can
Mailing: 747 Sheridan Boulevand, Und 2A - Lalsemoc, Were& 80211- Phone: 303338.970 - ORir¢®BeslEmineerinoU94.a
2869-2869 Teller alreet B.E.S.T.
Raged Numbec 19-1114
Samples taken from the exploratory boring were obtained for laboratory testing and inspected by the project
engineer. The results of the tests performed on the samples obtained from the test borings are shown on Table
1. Laboratory testing included index property tests; such as moisture content and density, swell/consolidation
testing and gradation analysis. The testing was performed on relatively undisturbed drive samples and were in
general conformance with recognized test procedures, primarily, ASTM and Colorado Department of
Transportation (CDOT).
FOUNDATION DESIGN RECOMMENDATIONS
The native sails are suitable to support lightly to moderately loaded slab-on-grade construction. Based on the
subsoil conditions encountered in the exploratory boring and the nature of the proposed construction, we
recommend that the structures be founded with spread footings bearing on native soils. The design and
construction criteria presented below should be observed for a spread footing foundation system.
1. Footings placed on the native soils should be designed for an allowable soil bearing pressure of 2,500
pounds per square foot (psf). Based on experience it is expected that movement of the footings, designed
and constructed as discussed in this section, would be approximately 1.5-inch or less. Differential
movements are estimated to be approximately 1/x to''/4 of the total settlement. Most of this settlement will
occur during the construction phase.
2. Spread footings placed on native soils should have a minimum footing width of 18 inches for continuous
footings and 24 inches for isolated pads.
3. Exterior footings and footings beneath unheated areas should be provided with adequate soil cover above
their bearing elevation for frost protection. Placement of foundations at least 36 inches below exterior
grade is required by the City of Wheat Ridge.
4. Continuous foundation walls should be reinforced top and bottom to span local anomalies by assuming an
unsupported length of at least 10 feet.
5. A grounding system (Wer Ground) may be installed where the grounding system is contained within the
exterior building wall and the concrete foundation wall. This is in place of having a copper ground rod
installed adjacent to the foundation wall.
6. The lateral resistance of a spread footing placed on undisturbed native soils or properly compacted granular
structural fill material will be a combination of the sliding resistance of the footing on the foundation
materials and passive earth pressure against the side of the footing. Based on the soil characteristics, the
resistance to sliding at the bottoms of the footings can be calculated based on a coefficient of friction of
0.42. Passive pressure against the sides of the footings can be calculated using an equivalent fluid unit
weight of 230 pounds per cubic foot (pcf). The at-rest lateral pressures on the walls can be calculated using
and equivalent fluid density of 60 psf per foot of depth. The active lateral earth pressures should use and
equivalent fluid density of about 45 psf per foot of depth. These lateral resistance values are working
values.
7. All loose or soft soils should be removed, and the footing bearing level placed on native soils or properly
compacted structural fill. The disturbed surface of the native soils should be compacted prior to concrete
placement
8. Interior backfill should consist of onsite native soils and should be placed in uniform lifts not to exceed 10
inches thick and compacted to at least 98% of the standard Proctor (ASTM D 698) maximum dry density
(5)
Locations: Summit evenly a Lakewood, LOWatlo • PasM 0 • PM1me: 970.409.9671) • MadrdBeslEnolne aingwAxorn
Mailing: 747 Sheridan Boulevani, Unit 3A • Lakemoc, edoado WP1I- Phone: 303216.970 • ORiceallaslEmineeringl154.cwn
2650-3680 Teller Sheds B.E.S.T.
Raged Number: 19-1114
and within 2 percentage points of the optimum moisture content. Interior backfill should extend laterally
beyond the edges of the footings at a distance at least equal to the depth of the fill below the footing
subgrade. Prior to the fill placement, any loose subgrade soils should be compacted. Any wet and soft
subgrade soils should be removed prior to fill placement. The backfill material should be free of snow and
ice, vegetation, topsoil, organics, trash, construction debris, oversized rocks greater than 8 inches in
diameter, and other deleterious material.
9. Exterior backfill may consist of the onsite native soils or imported structural fill and should be properly
placed and compacted to reduce the risk of settlement and distress. Onsite backfill material placed on the
exterior of the structure should be placed and compacted to at least 95% of the standard Proctor (ASTM D
698) maximum dry density within 2 percentage points of the optimum moisture content.
10. Backfill in pavement and walkway areas should also be compacted to at least 95% of the standard Proctor
(ASTM D 698) maximum dry density and within 2 percentage points of the optimum moisture content.
Care should be taken when compacting around the foundation walls and underground structures to avoid
damage to the structure. Hand compaction procedures may be used to prevent excessive lateral pressures
from exceeding the design values.
11. Backfill in landscaped areas may consist of native onsite soils or imported structural fill. It should be
placed in uniform lifts and compacted to at least 90% of the standard Proctor (ASTM D 698) maximum dry
density within 2 percentage points of the optimum moisture content.
12. Utility backfill should be compacted as appropriate for the proposed surface uses (landscape, building,
pavement, etc.).
13. All foundation and retaining structures should be designed for appropriate hydrostatic and surcharge
pressures, such as adjacent footings, traffic, construction materials, and equipment. The buildup of water
behind a wall or an upward sloping backfill surface will increase the lateral pressure imposed on a
foundation wall or retaining structure. An underdrain system should be provided to prevent hydrostatic
pressure buildup behind the walls. The lateral resistance values identified above assume drained conditions
behind the walls and a horizontal backfill surface. Refer to the Underdmin System section for further
information. Minor cracking of concrete foundation walls should be expected.
14. Based on our experience, we recommend all concrete exposed to the onsite materials meet the cement
requirements for Class 2 exposure of sulfate attack on concrete as presented in ACI 201. Alternatively, the
concrete could meet the CDOT requirements for Class 2 exposure as presented in Section 601.04 of the
CDOT Standard Specifications for Road and Bridge Construction (2011).
15. Depending upon depth of excavation and seasonal conditions, groundwater may be encountered within
excavations on the site. Pumping from sumps may be utilized to control water within excavations, if
necessary. BEST is available to provide further dewatering recommendations if this issue arises.
16. A BEST representative should observe all footing excavations prior to concrete placement to evaluate
bearing conditions.
CRAWLSPACE
The owner should be aware that crawlspace areas are typically subject to air quality issues and should be
constructed to provide proper ventilation and moisture management. Structural wood floor members over
crawlspaces and concrete walls should be treated to reduce or eliminate the propensity for mold or mildew to
(6)
Locations Summtl evenly a Lakexro4, eok2tlo • PasM 0 • PM1ma: 9]0.409.96]6 • MaalgBealEnolnaenmUSA.can
Mailing: 747 Sheridan Boul"ani, Und 2A • Lakemoc, Woatlo 80211• Phone: 303339.970 • ORire®BaslEmineerinoUS4.cwn
365a -36W Teller Slael B.E.S.T.
"g Numben 19-1114
form. The recommended clearance between floor members and the ground surface should meet applicable
codes. Further, it is recommended that a four (4) mil thick impermeable plastic sheet be placed over the ground
surface to reduce moisture migration into the crawlspace area. The sheet should be secured to the interior of
foundation walls. There should be a minimum 1 -foot of side lap between sheets and a minimum 2 -feet of end
lap. Ventilation and air quality control recommendations are beyond the scope of this report, a consultant
specializing in such issues should be contacted to provide further recommendations. BEST is capable of
providing these services.
The crawlspace ground surface should be sloped to the perimeter drain system and be free of depressions or
divots that could allow water to pond. Trenching within the crawlspace area is not recommended, apart from
trenching for interior drain or sump installation. Prior to the placement of the plastic sheeting, the crawlspace
should be free of standing and ponding water, overly moist soils, snow and ice, vegetation, topsoil, organics,
trash, construction debris, oversized rocks greater than 8 inches in diameter, and other deleterious material.
Isolated slab -on -grade pads may be used for utility appliances (hot water heater, furnace, water treatment
appliances, etc.). This system is appropriate provided flexible and collapsible connections are used and provide
allowance for up to 3 -inches of differential movement between floor/slab mounted appliances and fixed pipes
or ducts attached to structural elements of the building. Through -wall penetrations should be over -sized for
water, sewer, electrical connection, and any other forms of penetration to allow for movement In addition, all
plumbing and sewer lines should be isolated from the ground surface or foundation walls by at least 3 -inches.
ATTACHED GARAGE FLOOR SLABS
The interior area of the garage slab should be over -excavated to a minimum depth of 12 inches beneath the slab
and replaced with an imported structural fill or a non -expansive, predominantly granular material. The
geotechnical engineer should evaluate the suitability of fill materials prior to placement. Interior backfill
should be properly compacted and moisture treated and placed in accordance with the recommendations
outlined above.
To reduce the effects of differential movement, floor slabs should be separated from all bearing walls and
columns with expansion joints, which allow unrestrained vertical movement. Interior non-bearing partitions
resting on floor slabs should be provided with slip joints so that, if the slabs move, the movement cannot be
transmitted to the upper structure. This detail is also important for wallboards, stairways and door frames.
Slip joints which will allow at least 1.5 inches of vertical movement are recommended.
Floor slab control joints should be used to reduce damage due to shrinkage cracking. Joint spacing is
dependent on slab thickness, concrete aggregate size, and slump, and should be consistent with recognized
guidelines such as those of the Portland Cement Association (PCA) and American Concrete Institute (ACI).
The joint spacing and slab reinforcement should be established by the designer based on experience and the
intended slab use.
Slab performance is greatly dependent on the amount of moisture introduced to the underlying soils which
could result in excessive movement, causing uneven slabs and cracking. Proper surface goading and foundation
drain installation will help to reduce water infiltration in the sub -slab soils. Recommendations within the
Surface Drainage and the Underdoain System sections below, should be followed. Recommendations provided
in this section are meant to reduce the possible distress caused by slab movement but will not completely
eliminate risk. A stmctmally supported floor system should be used if the owner cannot toleoate potential
movement.
(T)
Locations Summit evenly a Lanewco4, eok2tlo • Psern 0 • PM1ma: 970AW.9670 • MatlitBealEnalneennowAxon
Mailing: 747 Sheridan Boul"aN, Unit 3A • Lakewood, Woado WPtt• Phone: 303218.970 • ORir¢®BasEmineeringl154.cwn
2M-2M Teller slreel B.E.S.T.
Rgxi Numhen 19-1114
DETACHED GARAGE FLOOR SLABS
Since the detached garage will be a stand-alone structure, we recommend a thickened edge slab founded on at
least 12 inches of over-excavated and replaced soils.
The interior area of the garage should be over-excavated to a minimum depth of 12 inches beneath the lowest
bearing elevation of the slab and replaced with an imported structural fill or non-expansive predominantly
granular material. Interior backfill should extend laterally at least 12 inches beyond the extents of the slab in all
directions and should be placed in accordance with the recommendations outlined above. Prior to the fill
placement, any loose subgrade soils should be compacted. Any wet and soft subgrade soils should be removed
prior to fill placement The backfill material should be free of snow and ice, vegetation, topsoil, organics, trash,
construction debris, oversized rocks greater than 8 inches in diameter, and other deleterious material.
The thickened edge slab may be 18 inches below grade and six inches above grade. Interior ribs may be used to
provide additional strengthistiffness to the slab as needed. If the slope of the ground precludes the use of a
thickened edge slab, we recommend a footing and stem wall placed in accordance with the recommendations
above.
To reduce the effects of differential movement, garage columns should be founded on isolated pads
with minimum widths of 24 inches and should extend at least 18 inches below grade. Pads should be separated
from the slab with expansion joints, to allow unrestrained vertical movement. Wallboards, stairways and door
frames testing on Floor slabs should be provided with slip joints so that, if the slabs move, the movement
cannot be transmitted to the upper structure. Slip joints which will allow at least 1.5 inches of vertical
movement are recommended.
Floor slab control joints should be used to reduce damage due to shrinkage cracking. Joint spacing is
dependent on slab thickness, concrete aggregate size, and slump, and should be consistent with recognized
guidelines such as those of the Portland Cement Association (PCA) and American Concrete Institute (ACI).
The joint spacing and slab reinforcement should be established by the designer based on experience and the
intended slab use.
SEISMIC CONSIDERATIONS
This area of Wheat Ridge is located in Seismic Design Category `B". The soil at the foundation level has a
very dense soil profile. The average soil profile in the top one-hundred feet provides an overall "stiff soil"
profile, which provides a Site Class of "D". Based on the subsurface profile, site seismicity, and the anticipated
ground conditions; liquefaction is not a design consideration.
SURFACE DRAINAGE
Proper surface drainage is very important for acceptable performance of the slab-on-grade during construction
and after the construction has been completed. The following recommendations should be used as guidelines
and changes should be made only after consultation with the geotechnical engineer.
1. Excessive wetting or drying of the excavation and underslab areas should be avoided during construction.
2. The ground surface surrounding the exterior of the building should be sloped to drain away from the
foundation in all directions. We recommend a minimum slope of 12 inches in the first 10 feet in unpaved
areas and a minimum slope of 3 inches in the first l0 feet in paved areas. Free-draining wall backfill should
be capped with approximately 2 feet of the onsite finer graded soils to facilitate surface drainage. Site
drainage beyond the l0-foot zone should be designed to promote runoff and reduce infiltration. These
(8)
Locations 5ummtl cwnly a Lanexco4, Casson • PasM 0 • PM1ma: 9]0.409.96]6- MaaasBealinelnee nswAxon
Mailing 747 Sheridan Boulevard, wd2A-1-akewaW, Cone E0211-Phone:303339.9]0. ORiceABaslEmineeringl194.cwn
2650-3680 Teller Saw B.E.S.T.
Rgasl Number 19-1114
slopes may be changed as required for handicap access points in accordance with the Americans with
Disabilities Act.
3. Xerlscaping should be considered with limited irrigation within 4 feet of the foundation walls. Roof
downspouts and drains should discharge well beyond the limits of all backfill and onto splash blacks.
UNDERDRAIN SYSTEM
The crawlspace level should be protected from wetting and hydrostatic pressure buildup by an interior
underdmin system. In addition, any interior slabs-on grade should be protected with a plastic barrier. It is
recommended that an impermeable plastic sheet be placed beneath the floor slab to reduce moisture migration
through the concrete slab. The sheet should be secured to the interior of the foundation walls. The should be a
minimum one-foot side lap and at least two feet of end lap.
The underdrain system should consist of a layer of free-draining granular material with a drain pipe connected
to a sump pit with a drain pipe to the exterior of the residence. The gravel layer should be encased in a non-
woven geotextile fabric. The free-draining granular material used in the drain system should contain less than
5% passing the No. 200 sieve, less than 30% passing the No. 4 sieve and have a maximum size of 2 inches.
The drains should consist of flexible or rigid drain pipe placed in the bottom of a trench and surrounded above
the invert level with free-draining granular material. The free-draining gravel should extend up to the top of
the footing. The drain lines should be placed at least 12 inches below the floor level and graded to sumps at a
minimum slope of 0.5%. The granular underdrain system should be sloped to a sump where water can be
removed by pumping. Sprayed on water-proofing should be used on the exterior of the foundation to prevent
infiltration of water. The geotechnical engineer should observe the underdmin and/or dampproofing prim to
backfill placement.
Any slab-on-grade construction precludes the need for an underdrain system. It is recommended that an
impermeable plastic sheet be placed beneath the floor slab to reduce moisture migration through the concrete
slab. The sheet should be secured to the interior of the foundation walls. There should be a minimum one-foot
side lap and at least two feet of end lap.
PAVEMENT THICKNESS DESIGN
The following pavement design criteria meets the City of Wheat Ridge pavement design guidelines. The
pavement design provided here is based on the minimum required pavement thicknesses as shown on the
standard Construction Details for Local Residential Streets with Parking.
If the recommendations provided below are followed, the proposed pavement sections should provide
acceptable performance for the property.
A pavement section is a layered system designed to distribute concentrated traffic loads to the subgrade.
Performance of the pavement structure is directly related to the physical properties of the subgrade soils and
traffic loadings. Soils are represented for pavement design purposes by means of a resilient modulus (MR) for
flexible pavements and a modulus of subgrade reaction (k) for rigid pavements. Both values are empirically
related to strength.
HOT MIX ASPHALT (HMA)
1. Subgrade Materials — Based on the results of the field exploration and laboratory test data, the pavement
subgrade materials at the site classify as A-6, in accordance with the American Association of State
Highway and Transportation Officials (AASHTO) classification system. Soils classifying as A-6 would
generally be considered to provide adequate subgrade support.
(9)
Locations, Sunni evenly a Lakexrotl, eok2tlo • PasM 0 • PM1ma: 9]6.409.96]6 • Maag6agEnalnea iasis can
Mailing: 747 Sheridan SaulavaN, Und 2A • Lakemoc, Were& 81211 - Phone: 303338.976 • ORr¢®6asingineerinoU54.a
3050-3666 Teller tersest B.E.S.T.
Rgact Numben 19-1114
The R-value of the onsite material (estimated to be l0) was converted to resilient modulus (MR) with a
value of 3,563 psi, using CDOT and AASHTO methods for conversion. Based on this, we have selected an
MR of 3,563 psi for pavement thickness design calculations.
2. Design Traffic — It appears that daily traffic at the site will be generally limited to automobiles that will
utilize the facility along with delivery and trash trucks on a routine basis. At the time of the report, traffic
data was not available. Therefore, we have estimated traffic usage based on similar facilities. We have
assumed an 18-kip equivalent single axle loading (ESAL) of 58,400 for areas restricted to residential
streets.
If the assumptions indicated above appear to be different than actual traffic values for the site, we should be
notified to reevaluate the pavement thickness requirements.
3. Pavement Sections — The pavement sections were calculated using the 1993 AASHTO pavement design
procedures. For flexible pavement design, an initial serviceability of 4.5 and 2.0, respectively, were
selected with a reliability of 70 percent. If otter design parameters are preferred, we should be contacted in
order to reevaluate the recommendations presented in this report.
Jefferson County minimum requirements for private streets, drives and fire lanes require the following
sections. Private drives, fire lanes, and parking should be paved with a minimum of 5.0 inches of full-depth
asphalt. As an alternative to the full-depth asphalt recommendations, a composite section consisting of 4.0
inches of asphalt over 6.0 inches of aggregate base course may be used for the parking areas.
Truck loading areas, dumpster pads, and other areas where truck turning movements are concentrated
should be paved with a minimum of 6 inches of Portland cement concrete. All concrete pavement areas on
the site should contain sawed or formed joints to Y4 of the depth of the slab at a maximum distance of 12
feet on center.
4. Pavement Material Recommendations — The asphalt mix should meet the latest requirements of the CDOT
Standard Specifications for Road and Bridge Construction. The asphalt placed for the project should be
designed in accordance with the SuperPave gyratory mix design method. The mix should meet Grading S
or SX requirements. A Superlative gyratory design revolution (NDES) of 75 should be used in the design
process. A PG 64-22 asphalt binder should be used for the mix.
5. Subgmde Preparation — The pavement subgrade should be scarified to a depth of 12 inches, adjusted to a
moisture content within 2 percentage points of the optimum moisture content and recompacted to at least
95% of the standard Proctor maximum dry density (ASTM D 698). Subgrade should not contain organic
matter or other deleterious substances.
The pavement subgrade should be proof-rolled with a heavily loaded pneumatic-tired vehicle of a heavy,
smooth drum compactor. Pavement design procedures assume a stable subgrade. Areas that deform
excessively under a heavy wheel load are not stable and should be removed and replaced to achieve a
stable subgrade prior to paving. The contractor should be aware that the clay soils, including onsite and
imported materials, may become somewhat unstable and deform under wheel loads if placed near the upper
end of the moisture range.
6. Paving should only be performed when subgrade temperatures are above 40° F and air temperature is at
least 40° F and rising.
7. HMA should not be placed at a temperature lower than 245° F for mixes containing PG 64-22 asphalt, and
290° F for mixes containing polymer modified asphalt. The breakdown compaction should be completed
before the mixture temperature drops 20° F.
8. The maximum compacted lift should be 3.0 inches and joints should be staggered. No joints should be
placed within wheel paths.
[10)
Locations : 5ummtl Cwnly a Lake ,LOWatlo-PasM0-Phan:970AW.9670- MategBestEnoloeetlmUSA.can
Mailing: 747 Sheridan Boulevard, Und M - Lakemoc, Woatlo 80311- Phoor 303339.970 - ORimnBeslEmineerinoUS4.cwn
2M-2666 Teller street B.E.S.T.
"act annual: 19-1114
9. HMA should be compacted to between 92 and 96 percent of Maximum theoretical Density, The surface
shall be sealed with a finish roller prior to the mix cooling to 185° F.
10. Placement and compaction of HMA should be observed and tested by a representative of am firm.
Placement should not commence until the subgrade is properly prepare, tested and proof -rolled.
11. Drainage — The collection and diversion of surface drainage away from paved areas is extremely important
to the satisfactory performance of the pavement structure. Drainage design should provide for the removal
of water from paved areas and prevent the wetting of the subgrade soils.
PORTLAND CEMENT CONCRETE (PCC)
1. Portland cement concrete should have a minimum compressive strength of 4,500 psi at 28 days and a
minimum modulus of rupture (flexural strength) of 650 psi. A COOT approved Class P mix design is also
acceptable. A job mix design is recommended and periodic checks on the jab site should be made to verify
compliance with specifications.
2. Portland cement should be Type II 'low alkali" and should conform to ASTM C 150. Portland cement
should conform to ASTM C 150.
3. Portland cement concrete should not be placed when the subgrade or air temperature is below 40' F.
4. Free water should not be finished into the concrete surface and finishers should not use a steel trowel on the
surface. Atomizing nozzle pregame sprayers for applying finishing compounds are recommended whenever
the concrete surface becomes difficult to finish.
5. Curing of the portland cement concrete should be accomplished by the use of a curing compound. The
curing compound should be applied in accordance with manufacturer recommendations.
6. Curing procedures should be implemented, as necessary, to protect the pavement against moisture loss,
rapid temperature change, freezing, and mechanical injury.
7. Construction joints, including longitudinal joints and transverse joints, should be formed during
construction or sawed after the concrete has begun to set, but prior to uncontrolled cracking.
8. All joints should be properly sealed using a rod back-up and approved epoxy sealant.
9. Traffic should not be allowed on the pavement until it has properly cured and achieved at least 80 percent
of the design strength, with saw joints already cut.
10. Placement of Portland cement concrete should be observed and tested by a representative of our firm.
Placement should not commence until the subgrade is properly prepared and tested.
CONSTRUCTION DETAILS
The design of a pavement system is as much a function of the quality of the paving materials and construction
as the support characteristics of the subgrade. The construction materials are assumed to possess sufficient
quality as reflected by the strength coefficients used in the flexible pavement design calculations. These
strength coefficients were developed through research and experience to simulate expected material of good
quality, as explained herein. During construction careful attention should be paid to the following details:
[111
Locations 5ummtl Cwnly a Lakewro4, Lok2tlo - PasM 0 - PM1me: 970AW.9670- MaaaiBeeEnolneemoUSA.corn
Mailing: 747 Sheridan BoulevauJ, Ju M - Lakemoc, Woado &6211- Phone: 303.236.976 - ORr¢®BeslEmineerinuM cwt
2M -26s6 Teller sheen B.E.S.T.
Proi lNumben 19-1114
• Placement and compaction of trench backfill.
• Compaction at curblines and around manholes and water valves.
• Excavation of completed pavements for utility construction and repair.
• Moisture treating or stabilization of the subgrade to reduce swell potential.
Design slopes of the adjacent ground and pavement to rapidly remove water from the pavement surface.
MAINTENANCE
Routine maintenance, such as sealing and repair of cracks, is necessary to achieve the long-term life of a
pavement system. We recommend a preventive maintenance program be developed and followed for all
pavement systems to assure the design life can be realized. Choosing to defer maintenance usually results in
accelerated deterioration leading to higher future maintenance costs, and/or repair.
SITE DEMOLITION
Demolition of the existing buildings should include the removal of foundation systems and loose backfill
found adjacent to the structures. Drilled piers, if encountered, should be truncated a minimum 3 feet below new
foundations, slab or pavement construction elevations. All materials derived from the demolition of the
structures, exterior f1dwork and pavements should be removed from the site and should not be allowed for use
in any on-site fills. Existing utilities and bedding to be abandoned should be completely removed. Existing
utilities and bedding may be abandoned in place if they do not interfere with planned development. Utilities
which are abandoned in place should be properly pressure -grouted to completely fill the utility
HOMEOWNER PRECAUTIONS
All new construction has an adjustment period after construction is completed. Exterior and interior
observation should be performed on a regular basis. The exterior backfill should be checked for positive
drainage away from the foundation. No ponding of water should be observed. Roof downspouts and splash
blocks should direct water away from the foundation. The discharge of any sump should be free of blockage
and discharge away from the foundation.
DESIGN AND CONSTRUCTION SUPPORT SERVICES
Please consider retaining BEST to provide the following services:
1. Review of the project plans and specifications for conformance with the recommendations provided in this
report.
2. Observation and testing to document that the intent of this report and that the requirements of the plans and
specifications are being followed during construction.
3. Identification of possible variations in subsurface conditions from those encountered in this study, so that
recommendations can be re-evaluated, if needed.
4. Preparation of a shoting plan, if necessary, for the protection of adjacent structures.
BEST is also available to assist the design team in preparing specifications for the geotechnical aspects of the
project and performing additional studies if necessary to accommodate possible changes in the proposed
construction.
[121
Locations 5ummtl county a Lakewood, eok2tlo • Penn 0 • PM1me: 970AW.9670- MaaaiBeMEnoloeedmUSA.Com
Mailing: 747 Sheldon Boul"ani, Und 3A - Lakemoct Woado WP11- Phone: 303219.970 - 0Rire®3estEmineerinoUS4.cwn
3650-3666 Teller Slael B.E.S.T.
Raged Numben 19-1116
LIMITATIONS
This study has been conducted in accordance with generally accepted geotechnical engineering practices in this
area for exclusive use by the client for design purposes. Copying of this report or portions of this report
without the express written permission of Best Engineering Solutions and Technologies, LLC (BEST), is
specifically prohibited. We make no warranty either express or implied. The conclusions and recommendations
submitted in this report are based upon data obtained from the exploratory test borings at the locations
indicated on Fig. 2, and the proposed construction. This report may not reflect subsurface variations that occur
between the explorations. The nature and extent of variations across the site may not become evident until site
grading and excavations are performed. If fill, soil, rock or water conditions appear to be different from those
described herein, BEST should be advised at once so that a re-evaluation of the recommendations presented in
this report can be made. BEST is not responsible for liability associated with interpretation of subsurface data
by others.
The scope of services for this project does not include any environmental assessment of the site or
identification of contaminated or hazardous materials or conditions. In addition, this study does not include
determination of the presence, prevention. or possibility of mold or other biological contaminants developing
in the future. If the owner is concerned about the potential for such contamination. other studies should be
undertaken.
Matthew A. Best, P.E.
Project Engineer
[131
Locations Summit Cwnly a Lakewood, Lok2tlo • PasM 0 • PM1ma: 9]0.409.96]0 • Matl bahatEnolnaenmUSA.corn
Mailing: 747 Sheridan Boulavani, Unit 3A • Lakemoc, Coloado 80311• Phone: 303336.970 • 0RiceABai;EmineerinoUS4.cwn
B.E.S.T.
TABLE 1.1
SUMMARY OF LABORATORY TEST RESULTS
PROJECT: 2850-2880 Teller Street PROJECT NO: 19-1114 DATE: December 23, 2019
LOCATION: Denver, CO SOURCE: Field Test Boring / Lab Testing
BNo.
Depth
Sample
Type
(Noma
Nat.
Remy
(MR
Natural
Moist.
(%1
ATTERBERG
LINITIS
GRADATION
%Swell2nd
Consolidation
Additional
Test
Results
(Note 3)
had Besmiptinn
LL
PI
ao
Gravel
+No.4
%Sash
-No.4
+No. 20
%Fines
-No. IN
I
1
CA
NI
u.o
36
13
3
26
72
sandy Cley
1
a
CA
119
14.0
59
sww.z%
sandy Cldy
1
9
CA
99
225
65
CT -0.61/,
Clayey sand
1
14
CA
97
266
59
sandy Clay
2
1
CA
1"
2414
40
22
68
sw-0s%
sandy Clay
2
6
CA
109
18.4
56
CT -03%
sandy Cley
2
9
CA
9021.0
70
sandy MY
2
14
CA
87
309
54
sandy Cley
NOTE 1 -sample Type
NOTE 2-SM1eae 541,19rh T,O,
NOTE 3- Additioml Ten Resulh
13S1Bag Sample
Cl- Unconfined Compression
TT-Tr,uxial Ten
A3=Aager Sample
C2 imauat Compression
Pf=Promor
Sf=SIMWy Tobe
C3=Fxkl I'mm,,elu
Ted
CAGlifamia Sample
C4-Poekeu Value
RA-Rvdm reading (VA)
RM—Remolded Sample
pH — pH of wit
I1134Hmd Onve
OR— Organs, cmrM of sail
APAirmied
TABLE: 1
Page 1 of 1
Lineations: Summit County 8 Lehewmd, Cobrado • Psalm 20 • PM1me:70.409.9670 • Man®BrstEmineeril cmm
Wiling: 747SEedden Boulevard, Unit 2A•Lakewomd, Cdomdo Mi I- Phone: 303.23RIT10. OffwABestEmnn rinmUSP
B.E.S.T.
SITE MAP
Project Number 19-1114
Locations: Sunni County& Lakewmtl, C kratlo - Plead 20- Pages: 9]0409.96]0- Matl(dBesrEnolneeringi com
Mailing: 747 Sheridan Boulevard, Unit 3A - Lakei Cdoatlo 80211- Phone: 303238.970 - ORice(dBestEnaineerinoll3Acom
IN
got to Scale
Figure 1
B.E.S.T.
BORING LOCATION
LEGEND: B-1—Ind4.ates approximate lwation of exploratory boring
Project Number 19-1114
Locations: Sunni County & Lakewmtl, Colorado - Plead 20 - PM1wn: 9]0409.96]0- MatlrdBestEnoineenngi com
Mailing: 747 Sheridan BoulevaN, Ond 3H - Lakewood, Cdoatlo 80211- Phone303.238.970 - ORicerdBestEnaineerinoll3Acom
Figure 2
APPROXIMATE
BORING
ELEVATION
B1
B2
5461'
5464'
0'
0'
/1/121,
14/12,
7
14/12"9/12p,5'
5'
5/12"
4/12"
0
10'
72ms7
V
(e)
7/12"
5/12"
S'
15'
(9)
20'
20'
36/12"
25'
25'
0'
30'
35'
35'
BORING LOG
Best
Lakewood Office:Engineering747Sherfdan
SoTlutions«nnotogtend«
Blvd,
Unit 2A
Lakewood, CO 80214
Project Location:
DRAWN BY: MKT
SCALE:
2850-2880 Teller .Street
REVIEWED BY: MAB
DATE: De mW 23, 2019
Veniw V-5'
HOivn W N/A
Denver, Colorado
PROJECT NO: 191114
PIGURE:3
. Concrete Driveway
Silty sandy clay, moist to very moist brown
® Claysmne, olive
toi
V Water Level, Time Alter Drilling (0= At Time of Drilling)
Disturbed Sample Collected
Tf-
T Undisturbed Sample Collected
X/12" Blow Counts; Number of Blows to Drive the Sampler 12-Inches (ASTM D-1586)
((X)) Depth of Caving Soils
NOTES:
1. The samples were collected on June 18, 2019 with a CME 45 truck mounted drill rig and 4" solid flight
auger.
2. The modification lines represent the approximate boundary between soil types and the transition may be
gradual.
3. The boring log(s) show subsurface conditions at the dates and locations indicated, and it is not
warrented that they ate representative of subsurface conditions at other locations or times.
4. Elevations are provided by Google Earth® and are considered approximate.
LEGEND & NOTES
EP'° Lakewood Office:
Enginsering
Geotechnical Engineering Study
747Sherfdan Blvd, Unit 2A
Solutions and
Technologies Lakewood, CO 80214
Project Location:
DRAWN BY: MET
SCALE:
REVIEWED BY: MAB
Vertical: N/A
2850-2880 Teller Street
DAM: Decamp¢ 23,2019
Horizontal: N/A
Denver, Colorado
PROJECT NO: 19-1114
FIGURE:4
Swell
-Consolidation
B1
at 4'
2%
1%
3
N
m 0%
6
-,
-2%
0.10
1.00
10.00
Load(KSF)
Swell
-Consolidation
B1
at 9'
2%
an
3
N
m d%
1
1%
-2%
0.10
1.00
10.00
Load(KSF)
Best Lakewood Office:
Swell -Consolidation Tests
E Bring 747Shendan Blvd, Unit 2A
lntlons and Lakewood, CO 80214
Technologies
Project Location:
DRAWN BY: MKT
SCALE:
2850-2880 Teller Street
CHECKED BY: MAB
Ver cal: NA
Denver, Colorado
DATE: December 23,2019
Horimntal:
PROJECT NO: 19-1114
RGURE:5a
Swell
-Consolidation
B2
at 1'
2%
1%
3
N
m 0%
6
-,
-2%
0.10
1.00
10.00
Load(KSF)
Swell
-Consolidation
B2
at 4'
2%
3
N
m d%
1
1%
-2%
0.10
1.00
10.00
Load(KSF)
Best Lakewood Office:
Swell -Consolidation Tests
E Bring 747Shendan Blvd, Unit 2A
lntlons and Lakewood, CO 80214
Technologies
Project Location:
DRAWN BY: MKT
SCALE:
2850-2880 Teller Street
CHECKED BY: MAB
Ver cal: NA
Denver, Colorado
DATE: December 23,2019
Horimntal:
PROJECT NO: 19-1114
RGURE:5b